THE NATION (2 June 2008, page 4)
claims that radio ranter Rush Limbaugh urged republican
"dittoheads" to re-register as Democrats and vote for
Hillary Clinton, the (presumably) weaker Democratic
candidate. ("Operation Chaos.") There were then emails from various
dittoheads to Limbaugh saying they'd nearly vomited but they did it,
etc.

John Kerry: "If it hadn't been for Republicans taking Democratic
ballots, Obama likely would have won Indiana
[which Clinton currently is credited as winning by 50.7 to 49.3%].
Rush Limbaugh was tampering with the primary.
The GOP has clearly decided they want Hillary as the candidate."

But THE NATION claims that is bull. They say there were 130,000
Republicans who voted in the Indiana Democratic primary, and exit
polls say they went 54-to-46 in favor of Clinton.
That gave her 10400 extra margin versus Obama (versus if no
Republican had voted).
Since that was not as large as Clinton's official margin of
14195 votes (margin according to CNN based on over 99% counted),
the Limbaugh effect was not responsible for her victory
(well, it was 73% responsible, but that is below 100).

But THE NATION's assessment disagrees with that of FOX NEWS,
Obama, and Limbaugh:

In an e-mail (acquired by or to Fox News) entitled "The Limbaugh
Effect in Indiana = 7 percent" Obama campaign spokesman Bill Burton
wrote: "According to the latest exit polling data, 17 percent of
voters in the Indiana primary today said they would vote for John
McCain in a Clinton/McCain match-up. Forty-one percent of that number
is constituted by people who voted Clinton in the primary but also
indicated they will vote for McCain in the general election. That
comes out to just under 7 percent of the primary electorate - the
number that may be attributed to a Limbaugh Effect." This 7% figure,
note, is 5 times the official 1.4% margin, thus proving the Limbaugh
effect responsible for Clinton's victory.

That assessment only works if you also count voters who were NOT
Republicans (i.e. were Democrats or Other) but nevertheless were
McCain supporters, who voted for Hillary Clinton. And since at least
some of those were honest votes, this was an exaggeration.

Limbaugh himself:
"I see the Obama campaign is saying Operation Chaos accounted for a
7-point bump for Hillary in Indiana. I think they are just jealous
that I out-organized them," Limbaugh told FOX News Tuesday night. "I
am extremely proud of Operation Chaos volunteers. I never doubted they
would triumph and it is a delight..."

MY CONCLUSION:
I think both THE NATION and Obama+Limbaugh have exaggerated their
(opposed) cases.

But the numbers are such that I think it is reasonably plausible the
Limbaugh effect WAS responsible for Clinton's victory. Namely the
NATION's analysis found it 73% responsible
and if you add in even a small fraction (i.e. just 7% of them)
of the number of non-republicans who were counted by Obama & Limbaugh
but ignored by THE NATION, then that's enough to push it over 100%.

--wds